The Lion · July 23 – August 22
August 21 Zodiac Sign
Born on August 21, you're usually a Leo, on the Leo–Virgo cusp — ruled by the Sun itself — radiant, generous and born to create.
Zodiac sign
Element · Modality
Fire · Fixed
Decan (third)
Mars-ruled
Birthstone
Peridot
Birth flower
Gladiolus
Season position
Day 30 of 31
What astrology says about a August 21 birthday
August 21 is day 30 of Leo season, so astrologers link it with the sign's core character: generous, creative, confident, warm-hearted. Traits astrologers commonly associate with Leo include warm, generous and big-hearted; natural creativity and flair for self-expression; confident leadership that motivates others.
A commonly cited growth area for Leo: a tendency to take over the spotlight. For the full picture of the sign, read the Leo guide.
3rd decan of Leo: Mars
Each sign is divided into three decans, 10° slices that the Sun crosses in about ten days each. August 21 falls in the third decan of Leo (about August 12–22), which the traditional Chaldean system assigns to Mars. Astrologers say that adds drive, courage and a direct approach.
Mars makes this stretch of the sign more assertive and action-minded — these are people who move first and think about the details on the way.
A Leo–Virgo cusp birthday
August 21 is the second-to-last day of Leo season, right beside Virgo. It is often said that people born this close to a boundary show traits of both signs: Virgo's analytical and thoughtful alongside Leo's generous and creative.
Astrology doesn't recognise a blended sign, and the exact moment the Sun changes signs shifts from year to year. Only a chart calculated from your birth year, time and place can confirm which side of the line you were born on.
The number 21 in numerology
The 21 is tied to sociability and self-expression. Birthdays on the 21st are read as charismatic, optimistic and at ease in a crowd.
Numerology is a separate tradition from astrology and is offered here for interest.
August birthstone and flower
The modern birthstone for August is Peridot and the commonly listed birth flower is the gladiolus. August falls in late summer in the north and late winter in the south.
Leo love and compatibility
Leo loves in technicolour. Romance for them is about devotion, admiration and a little theatre — date nights that feel like events, heartfelt compliments and a partner who is proud to be seen with them.
Astrology is a symbolic tradition, not a science, and interpretations vary between astrologers. This page is for reflection and entertainment, not prediction or advice.
Beyond your August 21 Sun sign
Your Leo Sun is one planet. Your Moon, Rising sign and the exact Mars-ruled decan details live in your full natal chart. Get yours free on Skygram.
Get my free birth chartAugust 21 birthday FAQ
What zodiac sign is August 21?
August 21 falls in Leo, which runs from July 23 to August 22 in the tropical zodiac. The Sun changes sign at a slightly different moment each year, so the boundary can fall a day or so either side of these dates. If you were born close to the edge, your birth year, time and place decide it.
Is August 21 a cusp birthday?
Yes. August 21 sits within a day or two of the Leo–Virgo boundary, and it is often said that people born this close to a boundary show traits of both signs. Astrologers still assign the Sun to one sign, and only a birth chart calculated from your birth year, time and place shows which.
Which decan is August 21?
August 21 is in the third decan of Leo (August 12–22). In the traditional Chaldean system this decan is ruled by Mars, which astrologers say adds its own flavour to Leo. Some modern astrologers assign decan rulers by element instead, which gives different planets, and decans are strictly 10° slices of the zodiac, so the date range is approximate.
What are the birthstone and flower for August?
The modern birthstone for August is Peridot and the birth flower is the gladiolus. These come from calendar tradition rather than astrology, and the lists vary by country and source.